Shelterflogger Philip G. Groves, T. C. Memo. 2026-86, filed 9/16/26, claims that because the Notice of Penalty Charge (Penalty Notice), a/k/a Form CP15, didn’t calculate how the Section 6707(a) shelterflogger chop was calculated (even though the NOPA he got did), he shouldn’t be chopped.

Judge Jeffrey S. (“Schwer”) Arbeit  says no hurt, no foul.

“Petitioner’s failure to allege prejudice is not so surprising. There does not appear to be uncertainty about how the penalty was calculated. The NOPA clearly showed the basis for the original penalty of $5,831,197 and an attached spreadsheet included a computation. Because of payments by others liable for the same penalty, the IRS determined that petitioner was liable for only a reduced penalty of $4,351,138. At the 2016 Appeals conference, the IRS explained the computation for the reduced penalty. When issued shortly thereafter, the Penalty Notice reflected the reduced amount. Even if the Penalty Notice did not include a computation, petitioner never seems to have asked for an explanation. He had no need to.” T. C. Memo. 2026-86, at p. 7.

Anyway, Tax Court caselaw says the statute requiring inclusion of calculation in the notice imposes no sanction for failure to do so, hence is a procedural irregularity, and only invalidates an administrative act if prejudice results.